Microsomal preparations from chick embryo cartilage are being utilized with sugar nucleotide precursors and PAPS to delineate the pathway of chondroitin sulfate biosynthesis. Microsomal preparations from mouse mast cell tumors are being utilized with appropriate radioactively-labeled sugar nucleotide precursors and PAPS to delineate the pathway of heparin (and related compound) biosynthesis. Tissue cultures of mast cells, which produce both heparin and chondroitin sulfate, are being utilized to investigate the subcellular sites of glycosaminoglycan biosynthesis and to follow the processes of packaging and export of the finished compounds. Radioactive precursors will be utilized to pre-label the cells before obtaining subcellular fractions. The fraction will be investigated to determine subcellular sites for glycosaminoglycan metabolism. The structure of a heparin proteoglycan isolated from rat peritoneal mast cells will be determined. The nature of the structure of heparin that binds to and activates antithrombin will be examined. The metamorphosing tadpole is being used as a model for the study of glycosaminoglycan degradation during rapid connective tissue change. Sub-cellular localization and characterization of the enzymes involved will be undertaken. Biosynthesis and turnover of the glycosaminoglycans during metamorphosis will be investigated. Cell surface heparin sulfate from cultured human skin fibroblasts will be examined as it relates to aging cell cultures and to cell lines obtained from different aged individuals.